This invention relates to a liquid ejecting apparatus including wiping member for wiping the nozzle opening formation face of a liquid ejecting head.
An ink jet printer is available as a liquid ejecting apparatus for supplying liquid stored in liquid storage member to a liquid ejecting head, and ejecting the liquid to a target from openings of a nozzle formed in the liquid ejecting head. This kind of printer includes a record head formed with a plurality of nozzles each having minute openings and ejects ink droplets from the openings of each nozzle. The ejected ink remains in the vicinities of the openings at the ejecting time or is deposited on the opening formation face of the record head because it bounces off a record medium such as paper or for any other reason. The deposited ink may be mixed with a different type of ink, may deviate the ink droplet ejection direction, or may cause nozzle clogging, to occur etc. Thus, the ink jet printer is provided with a wiping mechanism as wiping member for wiping the opening formation face of the record head. The wiping mechanism generally is formed of a material having flexibility such as an elastomer. When the wiping mechanism abuts the record head, the record head on a moving carriage abuts the wiping mechanism with standing still. Alternatively, the wiping mechanism itself moving, abuts the record head with standing still. While the wiping mechanism is deformed by abutting the record head, the wiping mechanism slides on the opening formation face of the record head for wiping ink deposited on the openings and their surroundings. The wiping mechanism then removes excessive ink and adjusts the ink meniscus at the nozzle tip.
When such a wiping mechanism abuts the record head, it needs to come in intimate contact with the record head at a comparative large pressure. Thus, the wiping mechanism requires adhesion properties to the opening formation face, namely, high flexibility and a high elastic coefficient for producing pressure for pressing the abutment face on the record head against the record head. However, to form the wiping mechanism of one member, it is difficult to satisfy the characteristics of both the adhesion properties and the elastic coefficient. Thus, a wiping mechanism formed using a plurality of members in combination is proposed. A wiping mechanism including a core and a surface layer covering the core for wiping the opening formation face of a record head with the surface layer is proposed. The core is made of urethane foam, etc., having water retentivity. The surface layer is made of a fiber material having water absorption properties. (For example, refer to JP-A-8-207292 (columns 3–6, FIG. 1)) Also other wiping mechanism is proposed that the wiping mechanism formed using materials different in elastic coefficient in combination for wiping the opening formation face of a record head with the member made of the material having the smaller elastic coefficient. (For example, refer to JP-A-2001-334676 (columns 5–14))
The wiping mechanism having the core formed with the surface layer made of a fiber material is excellent in the flexibility of the surface layer; however, when the water retention amounts of the surface layer and the core reach saturation levels, it is feared that the opening formation face of the record head may be contaminated by the absorbed ink. In a case of using pigment ink, there are possibilities of not only incompletely wiping the pigment deposited on the opening formation face of the record head, but also contaminating the nozzle openings, etc., by the pigment remaining on the fibrous surface layer.
As for the wiping mechanism formed of materials different in elastic coefficient, the wiping face abutting the record head is made of the material having the lower elastic coefficient, and the member made of the material having the larger elastic coefficient is placed near to the wiping face. Thus, the wiping face of the wiping mechanism becomes flat without becoming deformed like retroflexion, sinkage, etc. Therefore, it is possible to abut all area of the wiping face against the opening formation face at a smaller pressure as compared with a wiping face having irregularities. On the other hand, the wiping mechanism includes the member made of the material having the larger elastic coefficient at a deformed place below the wiping face and thus an inflection point occurs in the elastic coefficient from the bottom to the wiping face. Thus, when warpage occurs at the wiping time, there is a possibility that force will concentrate on the vicinity of the inflection point, producing deformation of bend, etc. The member made of the material having the larger elastic coefficient is inserted into the vicinity of the wiping part having the wiping face, is laid up on the wiping part, or is formed like waves and therefore parts manufacturing becomes complicated at expense in time and effort with an increase in cost.